Transseptal crossing, puncture, or catheterization is a means of gaining access to the left atrium 11 from the right atrium 12 of the heart 10. These chambers of the heart are shown in prior art FIG. 1 but since the patient is being viewed from the front, the left atrium 11 is shown on the right side and the right atrium 12 is shown on the left side in the drawing figure. This transseptal crossing, puncture, or catheterization was first described independently by Ross and Cope in 1959, as discussed in the article “Transseptal Catheterization in 2010: Crossing into a New Decade”, EP Lab Digest, February 2010. In FIG. 1 one may observe a transseptal crossing needle device 13 having an outer sheath 14, an inner dilator sheath 15, and a hollow needle 16 positioned within the inner sheath 15. The needle 16 has a curved portion 24 progressing towards a tip portion 16A. The inner sheath 15, as most clearly shown in expanded prior art view FIG. 2, has a partial conical tip tapering portion 15A and also is curved near its end by the forces exerted by the needle curved portion 24. The hollow needle 16 has a transverse cut tip portion 16A terminating in a tip 16AB at the end of upwardly sloping transverse end surface 16AA. Note that this surface 16AA slopes towards an upper concave curved inner wall 15B of the end portion of the inner sheath 15 and away from a lower convex curved inner wall 15C. Over the past 10 years or so, the number of transseptal crossings being performed has increased dramatically, driven mostly by the increase in atrial fibrillation (AF) ablation procedures within electrophysiology. This remains the predominant use of transseptal crossing devices. However, new minimally invasive percutaneous procedures related to structural heart are also being developed that use these devices. These procedures include the closure of atrial septal defects, left atrial appendage closure device implementation, and left ventricular assist device implantation.
Transseptal crossing across what is known as the septum 17 (fossa ovalis) as shown in FIG. 1 to gain access to the left atrium 11 is acknowledged as a critical and very dangerous part of all of the above procedures. Clinical guidelines support the use of multiple visualization checks when conducting this procedure with many physicians using a combination of fluoroscopy, echocardiography, pacing, and contrast injection, along with their own judgment and experience. For a number of different procedures, access to the left atrium 11 via the septum 17 (fossa ovalis) as described above is required. These procedures include mitral valve repair, mitral valvoplasty, atrial fibrillation ablation, and closure of left atrial appendage repair or closure.
Referring to FIG. 1, according to the prior art procedure the tapered conical end portion 15A of the inner dilator sheath 15, and more particularly the leading end 15AA, is moved down the septum 17 as shown by the arrow 18 until it reaches the relatively thinnest part of the septum 17. Thereafter the hollow needle 16 is pushed beyond the inner sheath end 15AA and penetrates through the septum 17. Thereafter the inner sheath 15 functioning as a dilator dilates with its conical end portion 15A the opening provided by the needle and pushes through, thus dilated the needle opening. Thereafter the outer sheath 14 is pushed along the inner sheath 15 through the dilated opening 17A. As shown in FIG. 4, the needle 16 and inner dilator sheath 15 are then withdrawn, leaving only the outer sheath 14 in the opening 17A, which is then available for use with medical instrumentation to be inserted into the left atrium 11 as described above.
The tip portion 16A of the needle 16 penetrates the septum 17 using ultrasound visualization.
Prior art FIG. 3 illustrates how the physician manipulates the inner and outer sheaths 15 and 14, and needle 16, for the above-described procedure. Initially before introduction into the human body, the needle 16 is pushed through the inner dilator sheath 15 until the tip portion 16A with tip 16AB is positioned near the tapered end portion 15A as shown in FIG. 2. A needle handle 19 firmly attached to an end of the hollow needle 16 is provided for manipulating the needle through the inner sheath 15. The needle handle 19 has a plurality of finger grip knurls 20. A leading end of the handle 19 has a pointing arrow 21 to indicate a rotational position of the needle 16, and particularly of the needle curved portion 24 leading to the tip portion 16A at the end of the hollow needle 16. The steel needle is pre-stressed into a curve at the curved portion 24 which causes a bending of the flexible inner sheath 15 and outer sheath 14 where the needle curved portion 24 is present.
Rearwardly of the finger knurls 20 is located a stop cock 22 for allowing in-flow of a liquid such as a dye introduced through a flexible hose 23 for delivery through the needle.
As illustrated in FIG. 3, the needle 16 passes through an inner dilator sheath handle 26 firmly attached to the inner dilator sheath 15. A knurled finger grip 26A is integrally formed at the needle entry end of the inner sheath handle 26 for finger gripping.
The opposite end of the inner sheath handle 26 butts against an outer sheath handle 27 having a knurled finger grip portion 27A. The outer sheath handle 27 is rigidly attached to the end of the outer sheath 14 for manipulation thereof. A hose 27B allows introduction of a fluid such as saline solution into the outer sheath 14 which surrounds the inner sheath 15.
The outer sheath 14 with the inner sheath 15 and needle 16 enter an outer wall of the human body 28 as shown at 28A and then are fed up to the heart through an artery, for example, and then to the septum 17 within the heart as explained in connection with FIG. 1 so as to create the desired diluted aperture 17A in the septum 17 as described above.
After the conical portion 15A of the inner dilator sheath 15 has been located as described above at the septum 17 in FIG. 1, then the physician pushes on the needle handle 19 to close the gap G between the leading end at arrow 21 of the handle 19 and the back surface of the inner sheath dilator handle 26. This causes the tip 16A of the needle to push out through the end 15AA of the inner sheath 15A to penetrate through the septum 17 such that thereafter a small portion of the needle at its tip portion now lies on the opposite side of the septum within the left ventricle 11.
During introduction and movement of the tip portion 16A having the transverse upwardly slanting angled end surface 16AA as shown in FIG. 2 to form the tip 16AB, shavings 25 can be scraped off by skiving at the upper concave curved inner wall 15B of the inner sheath 15 by the tip 16AB running along this concave curved inner wall 15B. This is undesirable and a disadvantage of this prior art device.
Another disadvantage of the prior art system is that presently the skill of the operator and “feel” are critical determining factors in the successful placement of the needle 16 and crossing of the fossa 17. Significant training is required in order for a physician to complete this procedure correctly.